Portable steam-boiler



No Model.)

J. R. MITCHELL & F. X. FISCHER.

PORTABLE STEAM BOILER.

No. 364.839. Patented June 14,1887.

N. PETERS. Phowlilhognpher, Washington, D- O.

' limited to these, we have extended the water- I are extending longitudinally the whole length of the boiler along the sides from the line. D

UNITED STATES PATENT QFETCE.

JOSEPH RAMSDEN MITCHELL AND FRANKXAVER FISCHER, 0E OAKLAND,

CALIFORNIA.

PORTABLE STEAM-BOILER.

SPECIFICATION forming part of Letters Patent No. 364,839, dated June 14, 1887.

Application filed Ntrernher 27, 1886.

T0 aZZ whom, it may concern:

Be it known that we, JOSEPH RAMsDEN MITCHELL and FRANK XAVER FIsoHER, of Oakland, Alameda county, State of California, have invented an Improvement in Portable Steam-Boilers; and we hereby declare thefollowing to be a'ful], clear, and exact description of the same.

Our invention relates to an improved construction for portable steam-boilers, and it is based especially upon the patent issued to us December 19, 1882, N 0. 269,308. In that construction we have shown water-legs carried straight up, so that the outer walls meet the boiler-shell in a line nearly or quite tangent to it, and this forms a sharp angular space within which it is difficult for water to circulate and where it would become filled with scale in a short time, and entirelyimpede the circulation of the water.

In our present invention, which is especially applicable to portable steam-boilers for burning straw or other light material, although not legs above or up to nearly the water-line and in the arc of a circle the center of which c0- ineides with the center of the boiler-shell, this,

of the water-legs.

Referring to the accompanying drawings for a more complete explanation of our invention, Figure 1 is a longitudinal vertical section. Fig. 2 is a transverse vertical section taken through the rear. Fig. 3 is-a vertical section taken through the front, Figs. 4 and 5 are views of the supplemental grate-section.

O is the ordinary multitubular boiler having the water-legs A A. extending the full length to D, as shown in Fig. 1. Theouter sheets of the water-legs A A, which were in the original patent riveted flat to the shell and standing tangent thereto, are in-the present case curved outward, so as to form an arc of a circle the curve ofwhich corresponds to that of the boiler-shell, as shown at B B, and this distance is retained to a point at or about the level of the water-line within the boiler, at which point the shell is curved inward until it brings the upper flange in contact with the Serial No. 220,004. (No model.)

boiler-shell to which it is riveted. The inner plates of the waterlegs are carried up nearly vertical or at a slight inclination, and have a flange bent so-as to fit against the lower part of the boiler-shell on each side, where they are riveted, the shells beingproperly stayed by bolts in the usual manner, as shown in Fig. 8.

Passages or openings 13 are made between the shell of the boiler and the upper part of the water-legs, so that a free circulation may be provided; By this construction the waterspace is considerably enlarged,thus affording a free circulation for the water and steam, and

also allowing a sufficient space for a reason are put in through hand-holes P P made in the outer sides of these curved water-legs,as shown in Fig. 2. It is thus easy to remove or replace the tube-sheet whenever desired. Hand-holes T T are also made in the rear ends of the water-legs for the purpose of cleaning them, and these can be more easily put in on account of the curve of the outer walls of the waterlegs, as before described. These holes are covered by removable plates, as shown.

The dry-pipe m extends along the upper part of the boiler and connects through a short vertical pipe with the steam drum or dome a. The dry-pipe is supported by brackets at each end,the forward one having a clainping'screw, 0, which being loosened the pipe may be drawn out through the opening P. a

The grate for straw-burning purposes consists of the longitudinal tubes a, the front ends of which are capped and may be slightly lower than the rear ends to insure circulation. The rear ends are turned up and are connected with the bottom of a transverse drum, 1). This drum extends across between the water-legs,

into which it opens at both ends, and it has the central pipe, 0, which connects with the boiler, so that water therefrom circulates within the tubes a and through the drum b. This drum also serves as a-water-back bridgewall, and, besides assisting in making steam, it is protected from the heat and prevented from burning out.

The tubes (0 are separated by considerable spaces, and when wood, coal, or othersimilar fuel is to be employed it is necessary toinsert grate-bars d, the spaces between which are much narrower. These bars have connecting transverse bars e,the ends of which are curved tofit the sides of the tubular bars, upon which they rest, as shown in Fig. 5. They may thus be removed or replaced at any time with little trouble.

Having thus described our invention, what we claim as new, and desire to secure by Let ters Patent, is-

1. The transverse drum forming a bridgewall at the rear of the furnace, and having its ends connected with the water-legs, and the central portion with the lower part of the boiler, as shown, in combination with the tubular grate-bars having their rear ends connected with the drum and their front ends at a lower level and closed, substantially as herein described.

2. The dry-pipe supported in brackets in the upper part of the boiler, the clamping bolt and nutby which the sides of the front bracket are compressed to hold the pipe, or loosened to release it, and the opening made in the boiler-head in line with the pipe, substantially as herein described.

3. The water-legs extending downward upon each side of the boiler, and having a length equal to or greater than it, said legs having openings and plates T at the ends, and their upper parts corresponding to the curvature of the boiler, substantially as and for the purpose herein described.

4. The boiler having pendulous water-legs extending downward upon each side, the upper part of the outer plates of said legs being curved so as to form an arc corresponding with the curvature ofthe boiler-shell, substantially as herein described.

5. The boiler having the water-legs extending downward upon each side, the outer plates of said legs having their upper edges riveted to the boiler-shell at or above the water-line within said boiler, and curved outwardly so as to form an are nearly or quite coincident with the curvature of the boiler-shell, whereby a space is leftbetween the shell and the outer sheet, substantially as herein described.

6. The boiler having the downwardly-extending water-legs upon each side, the outer plates of the legs being curved to an are nearly or quite corresponding with the curvature of the boiler-shell, and having the hand-holes or openings made in them coincident with the tube-sheet, substantially as herein described.

7. The tubular grate-bars and transverse water-back bridge-wall, as shown, in combination with the intermediate supplemental grates with transverse bars having their ends curved to fit the sides of the tubes and sup ported thereby, substantially as herein described.

In witness whereof we have hereunto set on r hands.

JOSEPH RAMSDEN MITCHELL.

FRANK XAVER FISCHER. \Vitnesses:

PAUL WnNon,

J OHN F. JORDAN. 

